South Africa says it is tightening hunting rules to try to combat illegal rhinoceros horn trading.

An environmental affairs ministry statement issued Monday said hunters applying for licenses must provide proof of hunting experience, such as membership in a hunting association, and a passport. The new rules also require South African authorities to consider whether the countries in which foreign applicants live have sufficient laws against illegal rhino horn trading.

South Africa has expressed concern about hunters from Vietnam, saying it has in some cases been difficult to identify Vietnamese nationals who request permits and determine whether they have the means for big-game hunting.

Vietnam also is seen as having lax laws on importing horns.

Demand among a growing middle class in Vietnam, where some people believe the horn has medicinal qualities, has helped spur a worrying increase in rhino poaching.

Last year, a record 448 rhinos were poached in South Africa, and the record will likely be surpassed. The latest government figures show 171 South African rhinos have been poached already this year.

"We once again make a call to members of the public to also help us in the fight against rhino poaching," environment minister Edna Molewa said in a statement Monday.